The present invention relates to testing apparatus and, in particular, to equipment which uses a bus or buses to connect selected ones of a plurality of test instruments to test terminals of a unit under test.
It is known to employ an assemblege of test instruments which are selectively switched to stimulate and measure a unit under test. This assemblage test instrument is designed generally so that many different types of units may be tested. This generalization can reduce effectiveness and often results in complex switching.
It is also known to use in digital equipment a bus line over which many different signals may be time multiplexed. However, these buses do not meet the special requirements involved in testing a unit quickly and with great flexibility.
Accordingly, there is a need for flexible switching equipment which allows a plurality of test instruments to be efficiently coupled through a bus lines to a unit under test to perform certain predetermined tests.